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just a few questions for a build

Crissman Kustoms

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First off, sorry if I’m posting this in the wrong section. There are so many different categories and I didn’t want to make several different posts. I recently purchased a 6w laser from wish. Was pretty cheap ($70) so I think it’s a good candidate for a build I’ve always wanted to make. The laser is great, very powerful, by far the strongest one I’ve had yet. The problem is it can’t be focused beyond 30” or so and it has to be run by a wall plug. The plug is a 12v output so I’m thinking I could run this on 3 18650 batteries. Maybe make a 3s2p cell. Would that work or fry the driver? The second question is there a way I can get this to focus at say 25’ or is it just the characteristics of this kind of laser not to hold a focus? If it is possible how would I go about building a lens for it? I have a good size property here and I would like to be able to mark trees from a distance or play with the fire without being right on it. Here is a link to the laser I bought. I would recommend it to anyone looking for a sweet laser cheap. My only complaint is that the lens has the tiniest bit of play in it making it hard to hold focus unless your close.
sorry I can’t post a link.
 



paul1598419

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If this is truly a 6 watt laser it has a long emitter with respect to the cleft, or fast axis, in it. That being the case is will not focus down to a dot unless you use a cylinder lens pair to expand the one axis. This can't be done with a normal host as you need a base to attach the C lenses to. You can certainly use batteries to supply your +12 volts as the driver will only pull the current it needs to drive the diode. Your batteries must be able to supply the necessary current without significant voltage sag under load. To burn at greater distances you'll need to add a beam expander. This will also reduce the divergence of the beam and can be used to focus the beam at closer distances.
 

Crissman Kustoms

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If this is truly a 6 watt laser it has a long emitter with respect to the cleft, or fast axis, in it. That being the case is will not focus down to a dot unless you use a cylinder lens pair to expand the one axis. This can't be done with a normal host as you need a base to attach the C lenses to. You can certainly use batteries to supply your +12 volts as the driver will only pull the current it needs to drive the diode. Your batteries must be able to supply the necessary current without significant voltage sag under load. To burn at greater distances you'll need to add a beam expander. This will also reduce the divergence of the beam and can be used to focus the beam at closer distances.
Thank you for the info. I figured that batteries wouldn’t be a problem but it never hurts to get a second opinion. As far as a beam expander can you recommend one to me or a link to something similar that would work? I’ve never messed with a laser like this before. Beyond 20’ the beam is a line at best more like a rectangle or a square depending on focus. The laser was listed as an engraver on wish and for 70 bucks to the door I think it was a good buy but I wouldn’t mind spending some money to get the optics right. I just need some guidance as to the best way to do it. I believe it is a true 6w but I have no way to test it. The paperwork says 6w constant and 10w max. Is it normal to have that big of a variation? This is the laser.
 

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paul1598419

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There are no direct diode lasers that output anywhere near 10 watts, so that is just Chinese hyperbole. You can get as much as 7 watts out of the NUBM44 V2 diodes, but they output about 27 watts of waste heat too. Sanwu sells a 3.3X beam expander that sells for less than $60.00 unless the price has gone up recently. But, a BE alone won't get that line down to a square which is what you are going for. You'll need a pair of 6X cylinder lenses to get it shaped that way and that takes a base right at the aperture of the laser to mount them on. Maybe that is a 6 watt output laser, but more likely it is less. Even at 6 watts the diode puts out a great deal of waste heat and that needs to be dealt with to have a decent run time. That is why they are actively cooled for engraving.
 

Crissman Kustoms

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There are no direct diode lasers that output anywhere near 10 watts, so that is just Chinese hyperbole. You can get as much as 7 watts out of the NUBM44 V2 diodes, but they output about 27 watts of waste heat too. Sanwu sells a 3.3X beam expander that sells for less than $60.00 unless the price has gone up recently. But, a BE alone won't get that line down to a square which is what you are going for. You'll need a pair of 6X cylinder lenses to get it shaped that way and that takes a base right at the aperture of the laser to mount them on. Maybe that is a 6 watt output laser, but more likely it is less. Even at 6 watts the diode puts out a great deal of waste heat and that needs to be dealt with to have a decent run time. That is why they are actively cooled for engraving.
When you say a pair of 6x cylinder lenses what do you mean? I have never seen anything like that.
 

paul1598419

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They come as either square lenses or circular and expand only one axis of the beam making to more of a square than a line. Google it to find out more.
 




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